The invention relates to a flexible tube for conveying a mixture of a liquid and a solid material containing objects with sharp points, edges or similar projections, the internal wall part of said tube consisting of an elastic material, especially rubber, in which a wearproof material is included.
Such a tube is known from British Patent Specification No. 1.576.996 (Vredestein). In this case the wearproof material consists of frusto-conical parts, which enclose one another to an important extent, so that there is always a layer of rubber between two parts.
Such a tube, which can have a wall thickness of some dozens of millimeters, can be bent to a limited extent only. High stresses occur in the rubber during bending and that is why in general such a tube is used only for almost static applications, e.g. the mutual connection of tube sections, which together can only constitute a limited angle.
When e.g. material sucked up by a dredger must be conveyed ashore over a considerable distance, such as e.g. some hundreds of meters, use is made of metallic tubes which, in view of the necessary flexibility, are coupled to one another by means of flexible tube sections, so that the pipeline may follow the swell and the movements of the dredger. Wind, current, swell and the like can exert important forces on the pipeline. To avoid rupture of the line it is therefore desirable, that the flexible tube can frequently bend over a considerable angle and, if necessary, collapse, which, however, is not the case with the above-described tube.
Also when, according to French Patent Specification No. 2.367.240, use is made of a wearproof material embedded in the rubber in the shape of rings with a round or flat section, provided in radial planes of the tube, such a tube will not be sufficiently flexible to allow the collapsing of the tube. Nor will this be the case when, also according to said French Patent Specification, a spiral of wearproof material is provided in the tube wall, as during the collapsing the spiral will be deformed to such an extent, that it will not regain its original shape.